What role does adsorption play in heterogeneous catalysis ?

Explanation

In heterogeneous catalysis, generally the reactants are gaseous whereas catalyst is a solid. The reactant molecule sare adsorbed on the surface of the solid catalyst by physical adsorption or chemisorption. As a result, the concentration of the reactant molecules on the surface increases and hence the rate of reaction increase. Alternatively, one of the reactant molecules undergoes fragmentation onn the surface of the `solid catalyst producing active species which react faster. The product molecules in either case have no affinity for the solid catalyst and are desorbed making the surface free for fresh adsorption. This theory is called adsorption theory.